C# 將 1D 數組拆分為每 N 個值的 2D 數組

Question

我有一個一維整數數組：

int[] array = { 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 30, 31, 32,33, 34,40,41,42,43, 44};

我想將此一維數組划分為 4 行 5 列的 2D 數組，其中前 5 個值進入第 1 行，接下來的 5 個值進入第 2 行，依此類推。 最終結果應如下所示：

數組2D：

[[10, 11, 12, 13, 14]
[20, 21, 22, 23, 24]
[30, 31, 32, 33, 34]
[40, 41, 42, 43, 44]]

實際上，數組會更長（可能超過 100 行），但列數為 5，行數可被 5 整除。例如，我已經簡化了。 這是我到目前為止所嘗試的：

int[] array = { 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 30, 31, 32,33, 34,40,41,42,43, 44};
int[,] array2D = new int[(array.Length/5),5];

int count_0 = 1;
int count_1 = 1;
int count_2 = 1;
int count_3 = 1;
int count_4 = 1;

for (int i = 0; i < array.Length; i++)
{
    if (i < 5)
    {
        // works for the first 5 values: 
        array2D[0, i] = array[i];
    }
    // I tried this approach for the rest where I try to say that if Im at index 5, 
    //and every 5th element from here, append to it to index[i,0] of array2D and so on. 
    // This do not work, and is what I need help with.
    else if (i >= 5 && i % 5 == 0)
    {
        array2D[count_0, 0] = array[i];
        count_0++;
    }
    else if (i >= 6 && i % 5 == 0)
    {
        array2D[count_1, 1] = array[i];
        count_1++;
    }

    else if (i >= 7 && i % 5 == 0)
    {
        array2D[count_2, 2] = array[i];
        count_2++;
    }

    else if (i >= 8 && i % 5 == 0)
    {
        array2D[count_3, 3] = array[i];
        count_3++;
    }
    else if (i >= 9 && i % 5 == 0)
    {
        array2D[count_4, 4] = array[i];
        count_4++;
    }
}

當然對於這個例子我只能說if > 5 && <10 {append to array2D}和if > 10 && <15 {append to array2D}等等，但我想要一些適用於數百個值的大型數組. 如果有人有更聰明的方法來做到這一點，請告訴我。

感謝您的任何幫助！

Answer 1

您可以只計算索引：

for(int i=0;i<array.Length;i++)
    array2D[i/5, i%5] = array[i];

Answer 2

您可以使用Enumerable.GroupBy完成 LINQ。

array.GroupBy(x => x / 5)
   .Select(x => x.ToArray())
   .ToArray()

Answer 3

您可以使用簡單的除法輕松計算索引。 該行是通過將 i 除以所需的列號來計算的。 該專欄只是該部門的提醒。

using System;

public class Program
{
    public static T[,] SplitInto2DArray<T>(T[] array, int rows, int columns) {      
        T[,] result = new T[rows, columns];

        for (int i = 0; i < array.Length; i++) {
            result[i / columns, i % columns] = array[i];    
        }

        return result;
    }

    public static void PrintArray<T>(T[,] array) {
        for (int i = 0; i < array.GetLength(0); i++) {
            for (int j = 0; j < array.GetLength(1); j++) {
                Console.Write(array[i, j] + " ");
            }
            Console.WriteLine();
        }
    }

    public static void Main()
    {
        int[] array = { 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 30, 31, 32, 33, 34, 40, 41, 42, 43, 44};

        int[,] splittedArray = SplitInto2DArray(array, 4, 5);

        PrintArray(splittedArray);
    }
}